非递归交换二叉树左右子树

 1 void exchange( struct node* node){
 2     struct node* tnode = node;
 3     struct node* tmp = NULL;
 4
 5     if(node == NULL)
 6         return;
 7
 8     while(1){
 9         tmp = tnode-> left;
10         tnode-> left = tnode->right ;
11         tnode-> right = tmp;
12
13         if(tnode->right ){
14             push(tnode-> right);
15         }
16
17         if(tnode->left ){
18             tnode = tnode->left;
19         }
20         else{
21             if(!empty()){
22                 tnode = top();
23                 pop();
24             }
25             else{
26                 break;
27             }
28         }
29     }
30 }